65 Ursae Majoris

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65 Ursae Majoris
Ursa Major constellation map.svg
Red circle.svg
Location of 65 Ursae Majoris (circled)
Observation data
Epoch J2000        Equinox J2000
Constellation Ursa Major
65 UMa ABC
Right ascension 11h 55m 05.74925s [1]
Declination +46° 28′ 36.6408″ [1]
Apparent magnitude  (V)+6.54 [2] (A/B/C = 6.7 / 8.5 / 8.32) [3]
65 UMa D
Right ascension 11h 55m 11.33152s [1]
Declination +46° 28′ 11.2150″ [1]
Apparent magnitude  (V)+6.965 [4]
Characteristics
65 UMa ABC
Spectral type A7 / A7 / A3 / ? / ? [5]
U−B color index +0.08 [2]
B−V color index +0.11 [2]
Variable type Algol [5]
65 UMa D
Spectral type A0p [6]
U−B color index +0.01 [2]
B−V color index +0.02 [2]
Astrometry
65 UMa ABC
Radial velocity (Rv)−3.90±4.4 [7]  km/s
Proper motion (μ)RA: 10.41 [1]   mas/yr
Dec.: 2.38 [1]   mas/yr
Parallax (π)4.72 ± 0.58  mas [1]
Distance approx. 690  ly
(approx. 210  pc)
Absolute magnitude  (MV)−0.05 [8]
65 UMa D
Radial velocity (Rv)−7.00±3.7 [9]  km/s
Proper motion (μ)RA: 11.82 [1]   mas/yr
Dec.: 0.39 [1]   mas/yr
Parallax (π)3.37 ± 0.56  mas [1]
Distance approx. 1,000  ly
(approx. 300  pc)
Absolute magnitude  (MV)−0.1 [10]
Orbit [5]
Primary65 UMa Aa1
Companion65 UMa Aa2
Period (P)1.73043 d
Inclination (i)86.5±0.2°
Semi-amplitude (K1)
(primary)		133.3±4.2 km/s
Semi-amplitude (K2)
(secondary)		135.7±4.2 km/s
Orbit [5]
Primary65 UMa Aa
Companion65 UMa Ab
Period (P)641.5±16.7
Eccentricity (e)0.169±0.048
Inclination (i)47°
Semi-amplitude (K1)
(primary)		13.7 [3] km/s
Semi-amplitude (K2)
(secondary)		19.9±2.7 km/s
Orbit [5]
Primary65 UMa A
Companion65 UMa B
Period (P)118.209±0.690 yr
Semi-major axis (a)208.2±9.7  mas
Eccentricity (e)0.504±0.006
Inclination (i)38.1±2.4°
Longitude of the node (Ω)92.1±4.2°
Periastron epoch (T)2447516.9±126.8
Argument of periastron (ω)
(secondary)		202.7±1.3°
Details
65 UMa Aa1
Mass 1.74±0.06 [5]   M☉
Radius 1.86±0.08 [5]   R☉
Temperature 8,000 [5]   K
65 UMa Aa2
Mass 1.71±0.06 [5]   M☉
Radius 1.81±0.08 [5]   R☉
Temperature 7,948±20 [5]   K
65 UMa Ab
Mass 2.4±0.4 [5]   M☉
65 UMa B
Mass 2.4±2.0 [5]   M☉
65 UMa C
Mass 2.01 [3]   M☉
65 UMa D
Mass 2.31 [11] (3.02 + 1.64 [3] )  M☉
Radius 2.93 [11]   R☉
Luminosity 79 [11]   L☉
Surface gravity (log g)3.85 [11]   cgs
Temperature 8,600 [11]   K
Age 525 [11]   Myr
Other designations
65  UMa, ADS  8347, CCDM  J11551+4629
65 UMa ABC: DN  UMa, BD+47°1913, HD  103483, HIP  58112, HR  4560, SAO  43945
65 UMa D: BD+47°1914, HD  103498, HIP  58117, HR  4561, SAO  43946
Database references
65 UMa AB
65 UMa C
65 UMa D

65 Ursae Majoris, abbreviated as 65 UMa, is a star system in the constellation of Ursa Major. With a combined apparent magnitude of about 6.5, [2] it is at the limit of human eyesight and is just barely visible to the naked eye in ideal conditions. It is about 760 light years away from Earth.

Contents

65 Ursae Majoris is a sextuple star system. It contains six stars in a hierarchical orbit where each star orbits its inner stars. Such systems are uncommon, with only a few sextuple stars known. [5] Higher-multiplicity star systems are uncommon because they are less stable than their simpler counterparts, and often decay into smaller systems.

Multiplicity

Aa1
Period = 1.73d
a = 0.2 mas
Aa2
Period = 641d
a = 11 mas
Ab
Period = 118y
a = 0.18″
B
3.4″ separation
C
63″ separation
D

Hierarchy of orbits in the 65 Ursae Majoris system

The central pair of stars, 65 Ursae Majoris Aa1 and Aa2, are both A-type main-sequence stars. These are relatively bright, white-colored stars that typically have masses from 1.6  M☉ to 2.4 M☉. [12] They have relatively low masses for A-type main sequence stars and have spectral types of A7V. [5] Its orbital period is 1.73 days. [5]

The innermost binary pair 65 Ursae Majoris Aa is orbited by another star, designated 65 Ursae Majoris Ab. It is a spectroscopic binary: while the pair cannot be resolved, periodic Doppler shifts in their spectra indicate that there must be orbital motion. 65 Ursae Majoris Ab orbits the inner pair with a period of 641 days (1.76 years) and an eccentricity of 0.169. [5]

65 Ursae Majoris B orbits the three inner stars every 118 years. It is separated from the triple by 0.18″ , and an astrometric orbit has been calculated. 65 Ursae Majoris C and D are common proper motion companions and are separated 4″ and 63″ respectively from the central system. [5] 65 Ursae Majoris D also appears to be a chemically peculiar star with higher amounts of chromium, strontium, and europium than normal. [13] Because of its unusual composition, determination of its stellar parameters is difficult; the effective temperature of this star may be 9,300 or 9,500  K , with the radius and the surface gravity determined for the star dependent on the effective temperature. [6] Speckle interferometry results have resolved 65 Ursae Majoris D into two components separated by 138  mas but this has not been confirmed by other observers. The two stars resolved differ in brightness by about two magnitudes. [14] An orbit for two stars has been estimated to have a period of about 79 years. [3]

Variability

A light curve for DN Ursae Majoris, plotted from TESS data DNUMaLightCurve.png
A light curve for DN Ursae Majoris, plotted from TESS data

65 Ursae Majoris A is a variable star with the variable star designation DN Ursae Majoris. The pair Aa1 and Aa2 form an eclipsing binary as they periodically pass in front of each other while orbiting. The primary and secondary eclipses are almost identical and the apparent magnitude of the system varies between 6.55 and 6.65 twice during each orbit of 1.73 days. [16] The brightness variation is very small because the non-eclipsing component Ab is the brightest of the three stars and contributes 80% of the visible light. [5]

Distance

Trigonometric parallax measurements made by the Hipparcos spacecraft put the 65 Ursae Majoris ABC system at a distance of about 690 light years (210 parsecs), and component D at about 1,000 light years (300 parsecs). [1] The dynamical parallax determined from the calculated orbits of the stars gives a distance of 763 ± 95 light-years (234 ± 29 pc). [5] Gaia has published measurements for the AB system and for component D, but they are both highly uncertain. Gaia Early Data Release 3 includes a somewhat more reliable measurement for the parallax of component C at 4.3897±0.0245  mas , [17] implying a distance of about 740 light years. [18]

See also

Related Research Articles

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<span class="mw-page-title-main">Omega Ursae Majoris</span> Binary system in the constellation Ursa Major

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<span class="mw-page-title-main">Iota Lyrae</span> Binary star in the constellation Lyra

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<span class="mw-page-title-main">S Antliae</span> Star in the constellation Antlia

S Antliae is a W Ursae Majoris-type eclipsing binary star in Antlia.

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<span class="mw-page-title-main">83 Ursae Majoris</span> Candidate binary star system in the constellation Ursa Major

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<span class="mw-page-title-main">HR 4072</span> Star in the constellation Ursa Major

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<span class="mw-page-title-main">RR Ursae Minoris</span> Star in the constellation Ursa Minor

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<span class="mw-page-title-main">TU Ursae Majoris</span>

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<span class="mw-page-title-main">TX Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

TX Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major. With a combined apparent visual magnitude of 6.97, the system is too faint to be readily viewed with the naked eye. The pair orbit each other with a period of 3.063 days in a circular orbit, with their orbital plane aligned close to the line of sight from the Earth. During the primary eclipse, the net brightness decreases by 1.74 magnitudes, while the secondary eclipse results in a drop of just 0.07 magnitude. TX UMa is located at a distance of approximately 780 light years from the Sun based on parallax measurements, but is drifting closer with a mean radial velocity of −13 km/s.

<span class="mw-page-title-main">AH Virginis</span> Star in the constellation Virgo

AH Virginis is a contact binary star system in the equatorial constellation of Virgo, abbreviated AH Vir. It is a variable star with a brightness that peaks at an apparent visual magnitude of 9.18, making it too faint to be viewed with the naked eye. The distance to this system is approximately 338 light years based on parallax measurements, and it is drifting further away with a mean radial velocity of 7 km/s. O. J. Eggen in 1969 included this system as a probable member of the Wolf 630 group of co-moving stars.

<span class="mw-page-title-main">VV Ursae Majoris</span> Variable star system in the constellation Ursa Major

VV Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated VV UMa. It is a variable star system with a brightness that cycles around an apparent visual magnitude of 10.19, making it too faint to be visible to the naked eye. The system is located at a distance of approximately 1,500 light years based on parallax measurements.

<span class="mw-page-title-main">AW Ursae Majoris</span> Variable star in the constellation Ursa Major

AW Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated AW UMa. It is an A-type W Ursae Majoris variable with an apparent visual magnitude of 6.83, which is near the lower limit of visibility to the naked eye. This is an eclipsing binary with the brightness dropping to magnitude 7.13 during the primary eclipse and to 7.08 with the secondary eclipse. Parallax measurements give a distance estimate of 221 light years from the Sun. It is drifting closer to the Sun with a radial velocity of approximately −17 km/s. The system has a high proper motion, traversing the celestial sphere at the rate of 0.216 arc second per annum.

<span class="mw-page-title-main">DW Ursae Majoris</span> Variable star in the constellation Ursa Major

DW Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DW UMa. It is a cataclysmic variable of the SX Sextanis type, consisting of a compact white dwarf that is accreting matter from an orbiting companion star. The brightness of this source ranges from an apparent visual magnitude of 13.6 down to magnitude 18, which is too faint to be viewed with the naked eye. The distance to this system is approximately 1,920 light years based on parallax measurements.

References

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  2. 1 2 3 4 5 6 Tolbert, C. R. (1964). "A UBV Study of 94 Wide Visual Binaries". Astrophysical Journal. 139: 1105. Bibcode:1964ApJ...139.1105T. doi: 10.1086/147852 .
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  4. ↑ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Zasche, P.; Uhlář, R.; Šlechta, M.; Wolf, M.; Harmanec, P.; Nemravová, J. A.; Korčáková, D. (2012). "Unique sextuple system: 65 Ursae Majoris". Astronomy & Astrophysics. 542: A78. arXiv: 1207.0651 . Bibcode:2012A&A...542A..78Z. doi:10.1051/0004-6361/201219134. S2CID   56328797.
  6. 1 2 Pandey, Chhavi P.; Shulyak, Denis V.; Ryabchikova, Tanya; Kochukhov, Oleg (2012). "Abundance and stratification analysis of the CP star HD 103498". Astronomical Society of India Conference Series. 6: 225. arXiv: 1106.3727 . Bibcode:2012ASInC...6..225P. doi:10.1111/j.1365-2966.2011.19281.x. S2CID   56288919.
  7. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv: 1606.08053 . Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID   119231169.
  8. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644.
  9. ↑ Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv: 0705.0878 . Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID   119323941.
  10. ↑ Gomez, A. E.; Luri, X.; Grenier, S.; Figueras, F.; North, P.; Royer, F.; Torra, J.; Mennessier, M. O. (1998). "The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars". Astronomy and Astrophysics. 336: 953. Bibcode:1998A&A...336..953G.
  11. 1 2 3 4 5 6 Glagolevskij, Yu. V. (2019). "On Properties of Main Sequence Magnetic Stars". Astrophysical Bulletin. 74 (1): 66. Bibcode:2019AstBu..74...66G. doi:10.1134/S1990341319010073. S2CID   149900274.
  12. ↑ Adelman, Saul J. (2004). "The physical properties of normal A stars". Proceedings of the International Astronomical Union. 2004: 1–11. Bibcode:2004IAUS..224....1A. doi: 10.1017/S1743921304004314 .
  13. ↑ Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 95: 135. Bibcode:1995ApJS...99..135A. doi: 10.1086/192182 .
  14. ↑ Balega, Yu. Yu; Dyachenko, V. V.; Maksimov, A. F.; Malogolovets, E. V.; Rastegaev, D. A.; Romanyuk, I. I. (2012). "Speckle interferometry of magnetic stars with the BTA. I. First results". Astrophysical Bulletin. 67 (1): 44. Bibcode:2012AstBu..67...44B. doi:10.1134/S199034131201004X. S2CID   122554107.
  15. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  16. ↑ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  17. ↑ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR .
  18. ↑ Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021). "Estimating Distances from Parallaxes. V. Geometric and Photogeometric Distances to 1.47 Billion Stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv: 2012.05220 . Bibcode:2021AJ....161..147B. doi: 10.3847/1538-3881/abd806 . S2CID   228063812.
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